Watkins-Johnson Company WJ-8718A/MFP Instruction Supplement page 87

TABLE 3-8
TABLE 3-9
Table 3-8. U7 Truth Table·
WJ-87I8A/MFP
Inputs Outputs
Enable Select
GI
G2B G2B
e
B A YO Y1 Y2 Y3 Y4
vee
GND AI5 AI4 AI3 AI2
1
0
0 0 0
0
0
I I I
I
I 0
0 0 0 I 1 0 I I I *
I 0 0 0
I
0
1 I 0 I 1
I
0
0 0
I I I I 1 0 1
1 0 0 I 0
0
1 I I I
0
Table 3-9. U8 Truth Table
Inputs Outputs
Enable Select
GI G2B G2A
e
B A YO YI Y2 Y3 Y4 Y5
WR
*U7YI A4-A5 A2 Al AO
I 0 0 0 0
0
0 I I I
1 I
1
0 0
0 0
1
1 0 I
1
I
1
1
0 0
0
I
0
I I 0 I I I
I 0 0 0 I
1
1 I 1
0
I 1
1
0 0
1 0
0
1 1 1 1 0 1
1
0
0 1 0 1 1 1 1 1 I
0
. The U8 inputs are the three least significant address bits of the bus, address bits 4
and 5, Y1 decode output from U7, and WR. Any microprocessor write cycle, to address 1x3x,
causes G2A and G2B to be low and G1 to be high through Nand gates U9B and U9A. The U8
outputs YO- Y5 are clock strobes which latch bus data into the write-only registers used for
storing frequency data for the LO synthesizers and BFO synthesizers. Table 3-10 lists the
binary equivalent of the four hexadecimal address digits, 1030 through 1035.
3-32